Engineering and Contracting . Lerel v/////////////////////////////- steel ffinefs Fig. 1—Head Frame Hoist. the market by French & Allen, manufacturers of con-tractors equipments, 508 S. Canal St., Chicago, 111. Between the timbers which carry the sheave and withinhead shaft is bolted a casting A within which runs abrake wheel B keyed to the shaft. The two slots, C, C,in the casting are eccentric with respect to the brakewheel; they provide for the brake shoe D as to the drawing, the shaft usually revolves inthe direction shown by the arrow, and so revolving thebrake shoe ri
Engineering and Contracting . Lerel v/////////////////////////////- steel ffinefs Fig. 1—Head Frame Hoist. the market by French & Allen, manufacturers of con-tractors equipments, 508 S. Canal St., Chicago, 111. Between the timbers which carry the sheave and withinhead shaft is bolted a casting A within which runs abrake wheel B keyed to the shaft. The two slots, C, C,in the casting are eccentric with respect to the brakewheel; they provide for the brake shoe D as to the drawing, the shaft usually revolves inthe direction shown by the arrow, and so revolving thebrake shoe rides up on the wheel with very little of the direction of revolution, as would resultfrom a falling bucket, carries the brake shoe down and the eccentric slot C causes it to wedge and stop thewheel. It the normal operation of the shaft is the re-verse of that indicated the brake shoe is shifted to the. Fig. 2—Safety Clutch for Hoist. opposite slot Cc. This reversibility of the braking actionis a particular feature of the device being described. An-other feature emphasized is its quick action. PRACTICAL CLOSURE SHEET FOR SINGLEWALL STEEL SHEET PILE COFFERDAMS. Contributed by Carl O. .lohnson, Department of Public Works, BridgeDivision, Cliicago, 111. Closing a single wall steel cofferdam is often a trouble-some procedure, especially when the work must be donein deep water, or where sheeting comes together ball toball or socket to socket. Mr. Murphey of the Great LakesDredge and Dock Co. devised a scheme which workedvery satisfactory in the steel dam for the Belmont , Chicago. Here the sheeting came together, ballto ball, in a wedge-shaped opening in about 15 ft. ofwater. The excavation inside the dam was subsequentlymade 20 ft. Two 35 lb., 24 ft. U. S. Steel sheets, with3xl0-in. S4S pine filler between, were lightly bolted to- SyiO-Pme ??i*s Washer :,;u nne .i
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicago, bookyear19
